Manufacture of monosodium phosphate



Patented Aug, 112, ltll d.

WALTER GLAESER, @E JBRQUKLYN, NEW 1 03K.

MANUFACTURE OF MQNUSG'DIEUM PHUSPHATE.

li'o Drawing.

v-ention being herein explained and the best til mode in which I have contemplated applying that principle, so as to distinguish it from other inventions.

The present invention relates to a new and improved method of manufacturing mono-sodium phosphate using either phosphate rock or dicalcium phosphate or any similar phosphatic material as a base material from whichthe mono-sodium phosphate is produced. To the accomplishment ofthe foregoing and related ends, the saidinvention, then, consists of the means hereinafter fully described and particularly pointed out in the .claims.

The following description sets forth in [detailone approved method of carrying out the invention, such disclosed mode, however, constituting but one of the various ways inwhich the principle of the invention may be used. I

lln carrying out the present invention, phosphate rock, dicalcium' phosphate, or a similar hosphatic material /is reacted. upon by sulphuric, acid and water sufficient in amount to produce mono-calcium phosphate according tothe well knownreaction:

The above reaction may be desirably carried out in a suitable tank which is equipped with a stirring or agitating apparatus, and also with heating means such, tor example, as a steam coil, in order that the mixture may be warmed to facilitate the reaction.

Heat, however, is not necessary and particularly when dicalcium phosphate is emplo ed.

fter the completion of the above reaction the calcium sulphate is removed by filtration and washed with water until entirely free from mono-calcium phosphate. The filtrate and the wash water are then united Application filed April 212, 11922.

Elerial No. MLMZ.

and a solution oi sodium'oxalate is'added which reacts upon the mono calcium phosphate with the production of mpno-sodium phosphate and calcium oxalate in accord ance with the following equation:

CaH,P U na c o na n r o 03,0 0,.

The solution containing the mono-sodium phosphate may then be evaporated and the mono-sodium phosphate recovered in the usual manner, that is, either in the solid -form or it may be changed to disodium phosphate by the addition of sodium carbonate solution:

The calcium oxalate may then be treated with' boiling sodium carbonate solution to convert it to neutral sodium oxalate according to the equation:

CaQQ, NagCO, f: (3900, Na C Q The resulting-sodium oxalate may then be. reintroduced into the process.

@ther modes'of applying the principle of my invention may be employed instead of the one explained, change being made as regards the method herein disclosed, provided the stepor steps stated by any of the following claims or the equivalent of such stated-step or steps be employed.

ll therefore particularly point out and distinctly claim as my. invention 2- I. In a. method of making mono-sodium phosphate, the'steps which consist in treatmg phosphate containingmaterial with sulphuric acid and Water-to producemono-calcium phosphate and then converting the mono-calcium phosphate formed to monosodium phosphate by the addition of sodium oxalate.

2. In a method of making mono-sodium phosphate, the steps which consist in react.- mg upon a phosphate containin material with sulphuric acid and water w ile mainwith sodium oxalate to produce mono-sodium phosphate, and then separating the mono-sodium phosphate formed from the calcium oxalate by filtration.

Signed by me, this 6th da of April, 1922.

WALTJE GLAESER. 

